Landscape engineering typically deals with large land areas and requires the input of several specialists. These include experts in earth engineering, water management, agrarian management, land economy, legal policy and transport infrastructure to name just a few. Furthermore, landscape interventions inevitably affect large numbers of people living on or near a particular sight. It is often critical for the designers of a landscape project to communicate their vision to the local inhabitants. It is therefore desirable that the tools used by landscape designers and engineers allow various specialists and lay people to participate in a collaborative design process.
Engineers and designers involved in landscape, architectural and industrial projects continue to put great emphasis on the use of physical models, even though computer simulation techniques which provide virtual visualizations are increasingly available. Road engineers employ physical models to better understand complex topographies. Contemporary landscape designers often insist on using physical models (which may be later digitized) in the early stages of design exploration, in the same way that automobile designers still work extensively with physical, tape and clay models, even though they have access to sophisticated computer techniques for modeling curved-surfaces.
There is great efficiency in representing spatial constructs with physical, tangible models since physical models are themselves spatial constructs differing only in scale or material from the final outcome of a design. Physical models offer an intuitive understanding of complex geometries and physical relationships that are difficult, and sometimes impossible, to effectively describe in any other way.
On the other hand, computer based models, while commonly being limited to producing two-dimensional, visual representations, offer many advantages over the physical model. The dynamic quality of the screen allows computational systems to represent entities or forces that change over time. They offer a vast increase in the efficiency of production, reproduction and distribution of models. They also offer the ability to work directly with numeric data and at accuracies that far surpass the tolerances of most physical models.
The recent explosion in mapping, scanning and positioning technologies has led to a wealth of useful landscape data, including high-resolution topographical maps, information on soil types, population densities, variance in vegetation species and so forth. There has also been great progress in the methods used to analyze such data. Landscape designers and engineers are now able to simulate the results of their decisions using the power of computation.
Despite this progress, there has been relatively little development in the interface through which landscape based information is presented and manipulated. Most three-dimensional renderings and simulations are still viewed in two-dimensions on a computer screen or on paper. It is an object of the present invention to improve that interface.
Consider the following scenario: A group of road builders, environmental engineers and landscape designers stand at an ordinary table on which is placed a clay model of a particular site in the landscape. Their task is to design the course of a new roadway, housing complex and parking area that will satisfy engineering, environmental and aesthetic requirements. Using her finger, the engineer flattens out the side of a hill in the model to provide a flat plane for an area of car parking. As she does so, an area of yellow illumination appears in another part of the model. The environmental engineer points out that this indicates a region of severe land erosion caused by the change in the terrain and resulting flow of water. The landscape designer suggests that this erosion could be avoided by adding a raised earth mound around the car park. The group tests the hypothesis by adding material to the model and all three observe the affect on the process of erosion over time.
The scenario described above is one example of how the principles of the present invention may be applied to simulate dynamic characteristics by projecting computed representations of those characteristics directly onto the surface of a malleable three-dimensional physical model.
Others have sought human-computer interfaces that would better deal with three-dimensional forms, but the prevalent use of the two-dimensional computer screen has made it difficult to combine the benefits of physical and digital models in the same representation.
Frazier's Three-Dimensional Data Input Devices as presented in Computers/Graphics in the Building Process, Washington (1982) and more recently Gorbet's Triangles described by Gorbet, M., Orth, M. and Ishii, H. in “Triangles. Tangible Interface for Manipulation and Exploration of Digital Information Topography,” Proceedings of Conference on Human Factors in Computing Systems (CHI '98), (Los Angeles, April 1998), ACM Press, 49–56, have explored approaches to parallel physical/digital interactions.
The Tangible User Interface described by Ullmer, B., and Ishii, H. in “Emerging Frameworks for Tangible User Interfaces,” IBM Systems Journal 393, 3, 2000, 915–931, is being increasingly accepted as an alternative paradigm to the more conventional Graphical User Interface (GUI), where the ability to manipulate objects in space is more fully utilized.
Wellner's Digital Desk described by P. Wellner in “Interacting with Paper on the DigitalDesk.” Communications of the ACM 36, 7, 86–96 (July 1993). illustrates the efficiencies of augmenting paper based office production with digital tools and methods for storage. Similarly Hinckley's neurosurgical interface described by K. Hinckley, R. Pausch, J. Goble and N. Kassell in “Passive Real-World Interface Props for Neurosurgical Visualization,” Proceedings of Conference on Human Factors in Computing Systems (CHI '94), ACM Press, 452–458, uses a position tracked doll's head and knife to allow users to dissect a graphical representation of the brain.
There have also been a number of impressive developments in combined graphical/physical interactions. Systems such as the Phantom Arm offered by SensAble Devices, http://www.sensable.com/, when combined with virtual environments or holography as describe by W. J. Plesniak in “Haptic holography: an early computational plastic,” Ph.D. Thesis, Program in Media Arts and Sciences, Massachusetts Institute of Technology, Cambridge, Mass. June 2001. allow for highly convincing interactions.
Special note is due to the work of John Underkoffler, called “The Urban Design Workbench,” which directly inspired the approach used in the present invention, and was described by J. Underkoffler and H. Ishii in “Urp: A Luminous-Tangible Workbench for Urban Planning and Design,” Proceedings of Conference on Human Factors in Computing Systems (CHI '99), Pittsburgh, Pa. USA, May 15–20, 1999, ACM Press, 386–393. The Urban Design Workbench uses digitally augmented tagged physical objects to represent buildings that can be rearranged to facilitate the process of urban design. Each of these approaches illustrates the enhanced interactions that are afforded by the use of tangible objects in human computer interaction. It is the goal of the present invention to combine the benefits of these approaches and provide an improved interface of practical value in the context of landscape analysis and other fields that offer similar challenges.
The present invention takes the form of a human-computer interface that computationally analyzes three-dimensional data using a malleable physical representation such as a bed of glass beads. A user of the interface directly manipulates the form of one or more physical objects while their changing geometry is captured in digital form and computationally analyzed in real time, and the results of the computation are projected back onto the physical modeling surface. The interface contemplated by the invention takes advantage of a human user's natural ability to understand and manipulate physical forms while harnessing the power of computational analysis to visually display meaningful data on the surface of these forms.
The invention may be used to advantage in a variety of applications. As described in detail below, the invention may be used to particular advantage in architectural and landscape design by employing selected, available simulation techniques to evaluate physical characteristics of a modeled form (e.g. elevation, curvature, contours, shadow, water flows) to better understand the behavior of different structures and terrains under different conditions.
This invention offers an intuitive alternative for modeling and analyzing three-dimensional objects and forms, such as architectural and landscape models, where a mesh surface is automatically generated in real time according to the changing geometries of physical surfaces and used to update computational simulations. This approach allows users to quickly create and understand highly complex topographies that would be time consuming and require an inappropriate degree of precision if produced using mice and keyboards in conventional CAD tools.
The present invention differs from existing approaches that employ position-tracked objects to capture position, form and shape data by instead directly detecting the surface geometry of a malleable object or set of objects, creating a seamless interface that allows engineers and designers to simultaneously interact with physical and digital forms of representation.
The present invention takes the form of methods and apparatus for modeling and evaluating the characteristics of three-dimensional forms. In accordance with a feature of the invention, a deformable translucent material that may be manually shaped is employed to define a modeling surface. Electromagnetic energy, preferably infrared light, is transmitted through the deformable material to produce radiation from individual regions of the modeling surface having an intensity that is related to the position of the region on the surface. The intensity of the radiation at different positions on the surface is measured, preferably by a digital camera, to produce radiation intensity data that is translated into elevational data that defines the geometry of the modeling surface. The elevational data is then processed to generate result data which specifies one or more characteristics at different points on or near said surface. A visual image corresponding to the result data is then projected onto the modeling surface. In this way, a user can form and modify the modeling surface by hand, and immediately view the computed characteristics of the modeled surface directly on its surface.
The preferred embodiment of the invention described in detail below employs the combination of an overhead camera to capture the surface geometry of a user-manipulated, deformable bed of translucent glass beads which defines a modeling surface, a processor for analyzing the captured surface geometry data in real-time to produce result data, and a video projector for illuminating the physical modeling surface formed by the beads with a visual representation of the result data.
The physical model creates and conveys spatial relationships that can be intuitively and directly manipulated by the user's hands. This approach allows users to quickly define and understand highly complex topographies that would be time consuming and require an inappropriate degree of precision if produced using conventional CAD tools. This alternative vision makes better use of the user's instinctive abilities to discover solutions through the manipulation of physical objects and materials.
These and other features and advantages of the present invention may be more clearly understood by considering the following detailed description of a specific embodiment of the invention.